1. Field of the Invention
The present invention relates to an improved projection type display apparatus that projects an image displayed by an image display device onto a screen by using light from a light source.
2. Description of the Related Art
There have been proposed various types of a so-called projection type display apparatus that displays an image displayed by an image display device on a screen or the like by using light from a light source.
FIG. 1 shows the optical system of a conventional projection type display apparatus.
In FIG. 1, light 200 from a light source 201 focuses at a lens 202, which condenses light on a lens 203 side, and the lens 203 turns the light into parallel light 204. The parallel light 204 is reflected substantially 90.degree. at color filters of green G, red R and blue B before it is transmitted through a liquid crystal display device 205. At this time, an image displayed by the liquid crystal display device 205 undergoes synthesis by the light from the color filters and is led toward a screen 207 through a projection lens 206.
In this conventional optical system, the distance from the light source 200 to the projection lens 206 is considerably long. This is due to the fact that the light source 200, the lenses 202 and 203, the color filters, the image display device 205 and the projection lens 206 are linearly arranged along the optical axis OP, which is bent only at one point, where the color filters are arranged. In order for these optical elements to be accommodated, the size of the conventional projection type display apparatus must inevitably be large. Further, there is a request for a projection of the image of the image display device which is clearer than ever.